Can be confused

Usage Notes

Word Origin & History

their c.1200, from O.N. þierra, gen. of þeir "they" (see they). Replaced O.E. hiera. Use with singular objects, scorned by grammarians, is attested from c.1300. Theirs (c.1300) is a double possessive. Alternative form theirn (1836) is attested in Midlands and southern dialect in U.K. and the Ozarks region of the U.S.